47,496 research outputs found
Dilaton transformation under abelian and non-abelian T-duality in the path integral approach
We present a convenient method for deriving the transformation of the dilaton
under T-duality in the path-integral approach. Subtleties arising in performing
the integral over the gauge fields are carefully analysed using Pauli-Villars
regularization, thereby clarifying existing ambiguities in the literature. The
formalism can not only be applied to the abelian case, but, and this for the
first time, to the non-abelian case as well. Furthermore, by choosing a
particular gauge, we directly obtain the target-space covariant expression for
the dual geometry in the abelian case. Finally it is shown that the conditions
for gauging non-abelian isometries are weaker than those generally found in the
literature.Comment: latex, 20 pages, no figure
Determining neutralino parameters in Left-Right Supersymmetric Models
We report exact analytical expressions relating the fundamental parameters
describing the neutralino sector in the context of the left-right
supersymmetric model. The method used for such a effects is the projector
formalism deduced without take into account the Jarlskog's projector formulae.
Also, expressions for the neutralino masses and the neutralino mixing matrix
are determined . The results are compared with numerical and analytical ones
obtained in similar scenarios in the context of the minimal supersymmetric
standard model.Comment: 34 pages, 23 figure
Human-Robot Collaboration as a new paradigm in circular economy for WEEE management
E-waste is a priority waste stream as identified by the European Commission due to fast technological changes and eagerness of consumers to acquire new products. The value chain of the Waste on Electric and Electronic Equipment (WEEE) has to face several challenges: the EU directives requesting collection targets for 2019–2022, the costs of disassembly processes which is highly dependent on the applied technology and type of discarded device, and the sale of the obtained components and/or raw materials, with market prices varying according to uncontrolled variables at world level. This paper presents a human-robot collaboration for a recycling process where tasks are opportunistically assigned to either a human-being or a robot depending on the condition of the discarded electronic device. This solution presents some important advantages; i.e. tedious and dangerous tasks are assigned to robots whereas more value-added tasks are allocated to humans, thus preserving jobs and increasing job satisfaction. Furthermore, first results from a prototype show greater productivity and profitable projected investment
Quantum structure of T-dualized models with symmetry breaking
We study the principal sigma-models defined on any group manifold GL x GR/GD
with breaking of GR, and their T-dual transforms. For abritary breaking we can
express the torsion and Ricci tensor of the dual model in terms of the frame
geometry of the initial principal model. Using these results, we give necessary
and sufficient conditions for the dual model to be torsionless and prove that
the one-loop renormalizability of a given principal model is inherited by its
dual partner, who shares the same beta-functions. These results are shown to
hold also if the principal model is endowed with torsion. As an application we
compute the beta-functions for the full Bianchi family and show that for some
choices of the breaking parameters the dilaton anomaly is absent: for these
choices the dual torsion vanishes. For the dualized Bianchi V model (which is
torsionless for any breaking), we take advantage of its simpler structure, to
study its two-loops renormalizability.Comment: 24 pages, no figures, latex2
Increasing access to credit through reforming secured transactions in the MENA Region
This paper provides a comparative summary of secured transactions systems related to the use of movable property as collateral in the MENA region vis a vis international practices in countries with modern secured transactions systems. The paper sets out the importance of introducing reforms in the area of secured transactions with the objective of increasing access to credit for businesses, particularly SMEs. The MENA region clearly lags behind all other regions in the introduction of secured transactions reforms. The paper summarizes many of the weaknesses common across the region. The two main critical areas that need urgent reforms are the creation of modern secured transactions laws and electronic movable collateral registries, and the need to improve enforcement mechanisms for security interests in movable property.Debt Markets,Bankruptcy and Resolution of Financial Distress,Access to Finance,Emerging Markets,E-Business
Target Space Duality I: General Theory
We develop a systematic framework for studying target space duality at the
classical level. We show that target space duality between manifolds M and
Mtilde arises because of the existence of a very special symplectic manifold.
This manifold locally looks like M x Mtilde and admits a double fibration. We
analyze the local geometric requirements necessary for target space duality and
prove that both manifolds must admit flat orthogonal connections. We show how
abelian duality, nonabelian duality and Poisson-Lie duality are all special
cases of a more general framework. As an example we exhibit new (nonlinear)
dualities in the case M = Mtilde = R^n.Comment: LaTeX, 29 pages, 1 eps figure. Added a couple of references and
corrected a couple of typos. An FAQ that discusses some subtle points may be
found at <http://www.physics.miami.edu/~alvarez/papers/duality/
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